


A Night of Healing

by ScyllaThePurple



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Dom/sub, F/F, Female My Unit | Byleth, Fluff and Smut, Light BDSM, Light-Hearted, Post-Time Skip, Trans Female Character, mtf!byleth
Language: English
Status: Completed
Published: 2020-01-28
Updated: 2020-01-28
Packaged: 2021-02-27 10:13:29
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,877
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22455514
Author URL: https://archiveofourown.org/users/ScyllaThePurple/pseuds/ScyllaThePurple
Summary: In the aftermath of a battle - Byleth is wounded and Mercedes is more than happy to be her healer, and maybe a little more.
Relationships: Mercedes von Martritz/My Unit | Byleth
Comments: 3
Kudos: 66





	A Night of Healing

**Author's Note:**

> Firstly, I haven't finished the game yet so my apologies if anything is inaccurate. Also, english isn't my first language, so there may be some mistakes. Anyway, I hope you'll appreciate it!

Byleth laid back into her makeshift bed with the slightest expression of pain on her face. One of her abdominal wounds hadn't been properly healed and she hadn't been able to sleep yet, late into the the night.  
But the battle had been won. Some more scars were an acceptable price for such victories, and she would rather take a wound on herself than on the ones she was supposed to guide and protect, any day.  
Back in the days of mere mercenary work with Jeralt, there would have been no magical healing at all. Sometimes, not even something to pass as a bed at night, only a cold and hard floor under her.

She truly considered herself lucky, despite the current climate of tensions. Fighting with friends at her side really made the difference.  
Byleth was also especially grateful for the presence of a certain friend, a healer she tried to keep an eye on at any time on the battlefield. More than anyone else, she wouldn't allow herself to let this person get hurt - or worse. She hated that, sometimes, her worrying and nervous glances to find her across the battlefield, meant that she might get distracted for a few, precious seconds. Byleth knew that she had no other choice. The risk was worth it if she could make sure that everything was fine, that her friend was safe.

Closing her eyes, Byleth tried to chase those thoughts away and finally manage to get some sleep.  
It wasn't long after that she heard some noise coming from just outside her tent. She immediately lent on her elbows to rise up in a sitting position. A faint, painful groaning escaped her lips.  
She felt around in the hopes of finding her sword, while she tried to make out something of the shapes in the dark.  
But her state of panic quickly came to an end as she heard a familiar voice.

"Oh, I'm sorry. Did I scare you? I didn't know if you were still awake."  
Byleth had a quiet sigh of relief before answering back.  
"It's alright. Is there a problem?"  
The silhouette in the dark moved, a little closer to her.  
"Not at all. I was wondering about your injury from today's battle. I'm not sure it had been properly treated, and I couldn't stop myself from thinking about it. I couldn't sleep either, so I found myself on my way to your tent."  
In Byleth's chest, a warm sensation suddenly spread. Those words were pleasing to hear, with so much care and affection in her voice.

Byleth confessed.  
"You're right. It still hurts a bit."  
The silhouette slightly shifted, now close enough for Byleth to make out Mercedes' features and her usual smile. Inside her, the warmth had turned into a furious turmoil of emotions, threatening to burst at any moment.  
She had never been used to strong feelings, either of friendship, hatred, or romance, for most of her life. But with her, all she needed was the sight - or even the faintest thought - of Mercedes' smile, to hear the cry of her own heart, loud and clear.

"Coming here was the right choice then. I may have just enough energy left to help my dear professor."  
Byleth felt the blond healer's hand on her shoulder, following her offer.

She turned her head a little, away from the smile. Byleth could now acknowledge when her own cheeks were a little red, and did the best she could to conceal it, if it could be seen with so little light.  
Hearing her nickname said like this, by this former student of hers, never failed to make her feel in a way that nothing else did. It had been something innocent, used by everyone to refer to her and her status.  
However, she had finally caught on the slightly different intonation that Mercedes had for it, and Byleth was suspecting that it wasn't that innocent anymore.

Despite her appearance of clumsiness, Mercedes was someone with deep beliefs and passionate in what she did. She was also gifted with an incredible easiness to read into other people's hearts.  
Maybe it would explain why she knew about Byleth's feelings when she was herself still in doubt about it.

"What is it? If you'd rather have me heal you in the morning, I can understand."  
Mercedes' voice was now clearly teasing, her tone depicting her feelings in a more forthright manner than her words.

Byleth sighed and gave in. If Mercedes really shared the same feelings as her, she had no reason to refuse.  
"Alright then, we can do this now, if you don't mind."  
She turned her head back towards Mercedes. She was, in a pretty obvious way, blushing just as much as her.

Byleth reached with her hand, full of hesitation on what she was supposed to do with it next. After a moment, she awkwardly put her hand on Mercedes' arm.  
Out of her control, her body had already seemed to act on his own, and leaned just a little closer to Mercedes, enough to feel the warmth of each other's breath. Her hand stayed still. She desperately needed to touch her more, to make contact with her skin, but Byleth was still unsure, her desires shrouded by the possibility of scaring Mercedes away if she'd let them out. She didn't want to appear forceful or too hasty.

However, Mercedes' answered by gentle gestures that only encouraged Byleth further. She took Byleth's hand in her own and locked eyes with her.  
Byleth, suddenly more confident, went for a kiss, driven wild by the thoughts of the soft lips of her beloved healer.

A playful humming came out of them when Mercedes interrupted Byleth, her fingers stopping her by taking hold of her chin. A look of surprise passed in Byleth's eyes, as she thought she had maybe done something wrong. But the grasp was delicate, despite being clearly firm in its intent.

"Please professor. Make yourself comfortable, I have to tend to your wound first."  
Mercedes moved her hand down to Byleth's chest, and gave it a slight but commanding push.  
Byleth let herself follow the movement. She was so captivated, she could barely pay attention to anything else, except the angelic face she couldn't look away from. Byleth even wondered if Mercedes could feel the panicking rhythm of her breath with the tips of her fingers pushing on her chest. Thinking about it only made Byleth more vulnerable, ready to follow any other instruction that Mercedes would have for her.  
It didn't take much longer. As Byleth ended up sitting down on her thin bed, legs spread in front of her and Mercedes between them, the girl asked a little more.  
"You'll need to take off your top, professor, so I can   
heal you properly."  
Her fingers left the chest, before quickly brushing against Byleth's arm. They both shivered from this brief contact, as the two women tried to restrain themselves just for a while longer.

Mercedes straightened her back, leaving Byleth some space. Once again, Byleth looked away as she started undoing the different parts of her outfit and slowly taking it off. She would have prefered to get the undressing part over as quickly as possible, but her wound still hurt, so she had to limit her movement and take her time to avoid worsening it.  
Finally, when her upper body was completely naked, she dared to look directly at Mercedes again. The eyes of the blonde woman had gone for an inspection of Byleth's wound across her stomach. However, Byleth had managed to catch something else, a look of fondness and appreciation in her eyes, silent compliments for the body exposed in front of her. Byleth started biting her lips, now filled with a lasting impression of being looked at with absolute love, something she had never known before.  
It made her only more acutely aware that she had her breasts naked in front of Mercedes, nipples slightly hardened by the cold air.

Byleth opened her mouth to talk, but Mercedes spoke first.  
"There is no need for you to speak now. You can talk only when I give you permission, or if you want me to stop."  
As she looked at Byleth, Mercedes had a new light in her eyes. Something that Byleth might have seen glimpses of before, but never so clearly. A very specific kind of love, one that Byleth had no issue accepting.  
"Understood, professor?"  
Byleth nodded affirmatively. It was strange, being put in such a position. The teacher, made docile by her student. The tactician, suddenly made to obey orders. Partly naked, and vulnerable, waiting for the next task. It wasn't much, but it made her powerless, entirely dependent on Mercedes. She had no reason to be scared, as she was already used to trust her with her life, and even more, when they were on the battlefield. But it was a very peculiar thrill, having her own former student, the most disciplined of them all, turn the tables on her.

Mercedes gently picked up a lock of Byleth's hair and twirled it around her fingers. Then, her lips curled in another smile and she spoke again, very softly, almost in a whisper, like a secret.  
"You're such a good girl."  
A second of realization later, and fire burned in Byleth's cheeks, or so it seemed with how hot and red they had suddenly become.  
She wasn't prepared at all for something like that, nor for Mercedes' visible easiness to take control. Mercedes herself looked a little red after her assertion. Byleth had such a need to blurt out how beautiful she was, how entranced she was by her lips and eyes, and how adorable each of her little expressions was. She wanted to tell her how much her words meant to her, and that she was perfectly happy obeying her commands, as her "good girl".  
But she knew now was the time for silence. She could always speak later.

"Move your arms away. I need to see the wound," asked Mercedes, with a hint of authority in her soft voice.  
As Byleth spread out her arms on the side to make sure it didn't come in between her and Mercedes, the blond healer clarified her order.  
"Behind your back, professor."  
Byleth shifted her position slightly, to sit properly while joining both of her hands in her back, almost as if they were tied by handcuffs.  
It was so simple, like a teacher with their student. Mercedes guided, Byleth followed. The former professor already loved her new status. It was a delightful feeling to hand over her power to Mercedes, and for once be the one who listens and attempt to do her best, in the hopes of praises - or even a smile, to reward her for her efforts. It was very new for her, and therefore exciting to discover.

Now that Byleth was topless and in a stable position, Mercedes started to actually focus on her wound. From what she could see in the dark, it wasn't very deep, but it cut across a major portion of her stomach and all the way to her side.  
Mercedes delicately placed her hands on each end of the wound. She whispered a few words, and a warm light started glowing from her palm. The injury began to slowly restore itself as the divine energy healed her.  
Byleth shivered slightly under the touch. It wasn't a reaction to any sort of pain. The sensation was nothing but pleasurable, and she craved even more. In her was already the need for it to continue endlessly, to have her tired body being soothed by the comforting magic of Mercedes, its energy connecting the two women as a visible, powerful bond.

"Stay still," asked Mercedes. "It's almost over."   
But the blonde healer caught the disappointment in Byleth's eyes and corrected herself.  
"It doesn't mean that we're done after that. I'm taking care of you tonight, as long as you keep being well behaved."

They shared a long look, a small grin on their lips.  
As soon as the wound was fully closed, Mercedes moved her hand to feel Byleth's restored skin and stomach - and the muscles underneath. In this simple gesture could be felt a lot of possessiveness for someone touching all of it for the first time. It wasn't needed for her to say anything. It was already hers.

"Now, you can speak," allowed Mercedes.  
Byleth pondered a few seconds for her first words, not sure how much time she had before going back to silence again.  
"Mercedes, you are-"  
One of the healer's fingers stopped her by pushing against her lips. Byleth knew it was a fairly agressive gesture for someone as peaceful as Mercedes, and the use of a single of her slender fingers, enough to silence her, turned her on to no end.  
"I think you're forgetting something, professor. Shouldn't you be a little more grateful?"  
She released Byleth' lips, instead cupping one of her professor's breast with her hand. She was so close now. Byleth could see the joy in her eyes, the intense yearning behind her grin, and she could already feel the love in her tender touch.  
"Thank you for healing me," said Byleth.  
Mercedes nodded slightly, and gave her a look that asked for a little more than that. Byleth understood, biting and licking her lips as she attempted to order thoughts in her brain and words in her mouth, as her mind and body seemed both on fire thanks to Mercredes, before she resumed:  
"I'm very grateful for your magic - and for all you've done. Thank for always healing me on the battlefield, and - and…."  
She lost herself a bit, her voice breaking. All of her words were sincere, and she was truly grateful for Mercedes to allow her to say it, without it sounding out of place or inappropriate.  
She really loved her. However, she had never found either the words or the strength to say it.

Mercedes could sense it. And it was an incredible relief, the weight of it suddenly lifted from her, to finally speak truthfully to her professor and being able to open up to one another.  
She did her best to maintain her composure and keep her soft yet dominant attitude, because she knew it was what Byleth was the most comfortable with at the time. Not that she didn't fully enjoy it as well. Mercedes adored her professor, and nothing made her happier than being able to order her around.  
She would have loved to get a collar around her lovely neck and tie a leash to it. She wanted to get Byleth's arms and legs bound together, and have her all for herself.  
But they had to do with what they had there, and a few orders will do just as well.

Mercedes began to gently caress one of Byleth's hardened nipple with the tip of her thumb, while she watched carefully for her lover's reaction. It didn't take long, as Byleth started to moan quietly.

"Please, please Mercedes, use me, just do whatever you want with me."  
Bylteh immediately looked away after blurting out her cry for pleasure. She was excessively blushing, and knowingly used her long green hair to cover part of her face and eyes.  
"What is it? You want to be used and you're ashamed of it?" teased Mercedes. "Don't be. Instead, you can tell me more about it."

Byleth felt lips and kisses on her neck, and shivers through her body as they trailed upward towards her ear.  
"Please…"  
There was no point in holding back now, with nothing to conceal anymore. At the same time, she knew there was no need to voice it all. Mercedes and her shared the same idea of what love between them would entail, she was sure of it. It was probably another one of the reason of why they had been so drawn to each other since the beginning - or at least, since Byleth had known more precisely what she was looking for.

Mercedes' lips had reached her ear and kept teasing by giving a gentle pull of her teeth on her lover's lobe. Quite satisfied with the moan let out by Byleth and the lovely crimson that continued to color her cheeks, Mercedes leaned in a little closer to whisper in her ear.  
"I asked you to tell me more about it. I shouldn't have to repeat myself, professor."  
Mercedes was nearly against her, their bodies inches apart. Byleth could see the healer's soft curves outlined by her clothes, and the lovely skin of her neck that she desperately needed to kiss while burying her hands in her short blond hair. It was so hard to resist to the simple desires blooming inside her, just a little longer, in order to reach a different kind pleasure.

"I want to take care of you, Mercedes. Please, just let me-", moaned Byleth, in a plea filled with longing.  
A thumb got through her lips and silenced her. It playfully caressed her tongue, as if it was taming a wild animal.  
"How sweet of you, professor. But it's not that easy, I'm afraid."  
Byleth's countenance briefly displayed a look of confusion, just before Mercedes started going a bit lower with her other hand. Byleth's expression shifted to surprise, then embarrassed delight as Mercedes reached even lower. Her hand squeezed the small bulge that was visible through Byleth's tight pants. The green haired girl's whole body reacted to the sudden touch, eyes squinting in pleasure, shoulders relaxing, heart beating faster, down to her toes curling up under her.  
Mercedes kept going with a gentle touch. She was already very fond of the adorable moaning from Byleth, of her half hard boner shivering and shifting under her caresses through the smooth fabric of her pants.

"Let me play with you for a bit," asked Mercedes. "If you behave well, I may allow you to attempt to pleasure me."

In a daze, Byleth nodded. The voice seemed so far, barely audible. Her mind was trapped by the feeling of Mercedes teasing her crotch. She was overwhelmed despite her short nails digging into her palm in an effort to withstand it.  
Was she really that easy to make squirm in pleasure, or Mercedes was that much of an expert on this?  
Byleth didn't have a lot of experience before that to compare it with, after all. But she felt so incredibly lucky. She would have thought it to be a dream, shaped by a exhausted body and a sudden fever into a delusional fantasy, if it hadn't been for the sensation of pleasure that she knew to be real.

Mercedes finally took pause.  
"You wanted this for a long time, didn't you?" teased Mercedes.  
Byleth could only nod in agreement, her head light and her breath short.  
"This is what makes you so amusing to play with," continued Mercedes. "But you're far from being truly satisfied, aren't you?"  
Her fingers trailed on Byleth's naked skin, right between her breasts and down to her well toned abdominal muscles. The green haired girl shivered under them, as it became more difficult to stay still and in position as time went on.  
"But if you actually want more… join your hands in front of you, professor. As if you were praying the Goddess."  
Byleth had no desire to keep Mercedes waiting and obeyed diligently, even if her arms were a bit tired after being kept behind her back for a while.  
"You're doing very well, professor !" exclaimed Mercedes.

Such a praise had the strangest effect on Byleth. It was a severe burn to her ego, to hear her own former student order her professor around, as if she was a well behaved pet who could learn tricks from her mistress, and being rewarded for them when she performed them well. Not even, at least, a reversal of their roles - no, Byleth wasn't allowed to be a student, instead being treated as a mere pet, or a submissive servant.  
At the same time, it was the most comforting thing that had ever been presented to her. So shameful and wrong, she could almost curl up and fully embrace this feeling inside of her. These words and attitude depicted her as so miserable, vulnerable, that it lifted all responsibilities from her.

Right now, she was fully eager to keep exploring this new feeling, all while discovering more of what Mercedes and her would be together.

Mercedes finally let her hands back down, but took her time to slowly undo Byleth's pants. The green haired woman seemed very sensitive in this area, in the best way possible. The slightest touch on the bare skin around her crotch made her squirm and moan with passion.  
Soon, one of Mercedes' hands was around her cock, while the other had a firm grasp on her thigh, now that it was out of her usual pants.  
Both of her hands started moving at the same time, gentle strokes and twists that made Byleth already lose her mind. Her penis was overwhelmed by the small mouvements of Mercedes' fingers. Pleasure was building up so quickly under her lover's touch, that she hadn't enough time to process how good it felt before the next wave came crashing all over her quivering body. Lacking the capacity to recover any control over herself or even any coherent thought, all she could do was attempting to stay as quiet as possible, but her groans kept threatening to become screams of pleasure at any moment - if the intensity would increase just a little more.

Mercedes chuckled as she kept moving her fingers with the same vigorous energy. Somehow, she was surprised by how easily her professor had been overcome by her teasing and made into an obedient pet, uselessly drooling and moaning.  
Byleth's half-hardened cock was now fully wet with precum, and the woman looked a little messier by the second. She was now rambling and swearing as quietly as she could, with a blank stare, probably lost in her own headspace.

To Mercedes, it was the most superb of sights. The one she had yearned for since her time at Garreg Mach, almost naked in front of her, devoted to her, and drowning in pleasure all thanks to her.  
"You're so beautiful, professor", she whispered, but it was clear that Byleth couldn't hear her, even if she had spoken louder.  
Now, she couldn't have her good girl not listening to her, could she?

Mercedes raised up a little bit, her hand letting go of Byleth's thigh while the other kept stroking. She firmly grasped Byleth's hair from the side of her head.  
With the hint of a sadistic smirk on her lips, she pulled on it fiercely. It caused Byleth to snap out of her trance, into painful sounds that replaced her moans. Mercedes twirled the hair around her fingers, playfully.

"You won't be able to come, right professor?" asked Mercedes.  
Byleth answered only with multiple silent nods. Her usually stoic countenance was disturbed by the tense expression of someone having to keep quiet on the edge of an impossible orgasm, while some enjoyment could still be read on her face, from the arch of her eyebrows to her eyes almost rolling back.  
Mercedes already had her doubts that Byleth must had some limitations with her body. Although she found no reason for it to be bothersome. As long as it didn't stop them from sharing these moments together - as long as their feelings could flow from one to the other, there was no reason to be worried.

The blond healer pulled on the strand of hair once again, this time to force Byleth to get closer, until their lips met in the warmest of kisses. Mercedes could feel Byleth's restlessness, her passion and her longing, all in the movements of her lips against hers, with a few shy contacts of their tongues.  
Byleth seemed to lack any form of patience, and it turned their kiss into a wild mess without any second to lose. She didn't even know how long it could last, thus why she wouldn't want to waste any of them. After being teased for so long, the woman craved for their physical connexion, finally being allowed to touch her lover as a reward. She dared to lean in even more than the requirement from Mercedes' pull on her hair. She let their breasts meet as well, soft clothing on naked skin, brushing against each other. Byleth wished she could take them in her hand, after watching Mercedes' body for so long, a sting of shame in her own chest each time she had taken a discreet glance.

But now that she knew that her attractions were welcome, all of her desires had been acutely amplified.

Before Byleth could freely enjoy their embrace, Mercedes broke it off.  
"Enough. That's enough, professor."  
As Byleth furrowed her brow in apprehension, Mercedes continued, reassuring.  
"I'm too worked up. Can you take care of me now, my dear Byleth?"  
Her voice almost ran out of air at the end of her sentence. Mercedes absolutely meant her words. She was drenched down there and needed some kind of stimulation to appease the sexual tension that had been building up since she had begun playing with her lovely toy.  
Every second spent looking at Byleth being a disheveled hot and naked mess with her inviting ample breasts, her lips glistening with their saliva and such a wild look in her eyes, was turning Mercedes on a bit too much, almost to the point of losing control. She could not wait any longer.

Byleth answered, her voice soft and kind, a whisper barely spoken.  
"Of course."  
Mercedes shivered like never before. She tried to calm herself down, but now the attempt was nothing but pointless.  
Byleth was already undoing her clothing, her fingers soon making their way to the naked skin. Mercedes guided her head towards her crotch with a far from gentle grasp on Byleth's hair. At the same time, they busied themselves with pushing her clothes aside hastily, until Byleth's mouth was against her sex. She kissed her slit, her movements erratic and proof of her inexperience, but Mercedes didn't care much. There was something endearing in Byleth's attempts to please, as her lips wandered around and kissed again and again until Mercedes gave her first signs of satisfaction.  
Byleth looked for the spots that made her lover's thighs fondly press against her face, and the ways to kiss so Mercedes would squirm from the touch of her lips. After some positive reaction from Mercedes, Byleth felt emboldened enough to start teasing with her tongue.  
As an immediate response, Mercedes pulled harshly but briefly on the strands of hair once again.

"Don't be shy, you can keep going" she demanded, her wording gentle but her tone more commanding than ever.  
She knew how close Byleth was to help her reach the sensation she was looking for, and the thought was setting her mind ablaze. Mercedes arched her back, both hands now in Byleth's hair, mentally begging her to go just a little deeper. She rocked her hips forward, in frenzied motions that managed to place her in the right spot to properly receive all of Byleth's attention. Her abundant juices mixed freely with Byleth's saliva in a chaotic but joyful dampness.

And Byleth, Byleth was exactly where she wanted to be. Intimate beyond what she would have thought possible with the one she loved, close to the extent of not needing to talk anymore, each being able to interpret the other's gestures and moans, in a fragile harmony of their bodies that guided them both towards a different form of bliss.  
Byleth was the first of the two to realize that Mercedes had reached her orgasm - she could see her legs suddenly tensing up, her breaths losing their rhythm, and felt her fingers sinking into her head, like claws looking for a semblance of stability in the the turmoil of emotions raging inside her.

Mercedes was so caught up in the moment, head lost in the millions of things happening in her feelings, that she was surprised when she finally understood she was coming. It was dizzying, her head light, her heart beating too fast for her to keep up.  
Pleasure blinded her, robbing her of the sight of Byleth. Nevertheless, she actually thought of herself as whole, for the first time since she had met Byleth. Their bodies were close enough for her to sense her presence in blindness, Byleth's warmth near her, the tips of her hair strands brushing against her skin, her lips and tongue still fondly kissing her clit.  
Mercedes immersed herself fully in the ocean of heavenly sensations, all of it carrying the strength of their love. It went from almost brutal to incredibly gentle in a matter of seconds.

And then, when she came back to herself, Byleth was at her side. They embraced each other, and in the same movement, lied down together.  
Sleep came quickly for both of them. They had never had a night so peaceful.

**Author's Note:**

> Thanks for making it to the end lol.  
> If you wanna talk or stick around to know when I'll post more fics, you can hit me up whenever on my twitter, https://twitter.com/PurpleScylla  
> I'm always happy to talk about f/f stuff or FE in general!


End file.
